Method and device for determining DOP value of orbital clock difference of low-orbit satellite

Abstract

The invention provides a method and a device for determining a DOP value of an orbital clock difference of a low-orbit satellite. According to the GNSS satellite-oriented measurement geometry of the low earth orbit satellite, based on the carrier phase and pseudo-range ionosphere-free combination observation equation corresponding to the current orbit determination method, obtaining a form covariance matrix of the low earth orbit satellite orbit and the clock error parameter under the earth-fixed coordinate system; and according to the form covariance matrix of the low-orbit satellite orbit and the clock correction parameter under the earth-fixed coordinate system, determining a precision factor DOP value of the low-orbit satellite orbit and the clock correction parameter under the earth-fixed coordinate system, and based on the method, obtaining each precision factor DOP value through calculation under the condition that a real result of low-orbit satellite precision orbit determination timing cannot be obtained. According to the DOP value of each precision factor, the strength of the observation model can be described, the form precision of each parameter is calculated, and the correlation among the parameters is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite positioning and timing, and in particular to a method and device for determining a DOP value of a low-orbit satellite orbital clock error. Background Art

[0002] Thanks to the low altitude, high speed and low cost of low-orbit satellites, the low-orbit enhanced Global Navigation Satellite System (GNSS) positioning, navigation and timing has a series of advantages such as strong signal strength, short convergence time and whitening of multipath effects, and has received more and more attention in recent years. In order to better utilize low-orbit navigation signals to achieve high-precision real-time positioning and timing on the ground, the system requires users to broadcast high-precision low-orbit satellite orbit clock products in real time and evaluate the accuracy of the orbit clock form, so as to facilitate the use of low-orbit enhanced GNSS ground positioning, navigation and timing accuracy users.

[0003] The existing Dilution of Precision (DOP) indicator is aimed at ground users based on the pseudo-range single-point positioning method. The Dilution of Precision (DOP) value is used to describe the strength of the observation model through the geometry of the GNSS satellites that can be received. The DOP value and the given observation prior / posterior root mean square (RMS) are directly used to calculate the formal accuracy of the position and clock difference.

[0004] The current technology does not have a method to determine the DOP value of the precision factor for precise orbit determination and timing of low-orbit satellites using carrier phase and pseudorange observations. It is impossible to distinguish the difference in the DOP values ​​of dynamic and kinematic orbit determination and timing, and it is not convenient to describe the model strength and formal accuracy of the precise orbit determination and timing results of low-orbit satellites. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a method and device for determining the orbital clock error DOP value of a low-orbit satellite, specifically comprising: In a first aspect, the present invention provides a method for determining a DOP value of a low-orbit satellite, comprising: According to the measurement geometry of the low-orbit satellite facing the global satellite positioning system GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained; According to the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system, the precision factor DOP value of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system is determined.

[0006] In a second aspect, the present invention further provides a device for determining a DOP value of a low-orbit satellite, comprising: The first processing module is used to obtain the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system according to the measurement geometry of the low-orbit satellite facing the GNSS satellite and based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method; The second processing module is used to determine the precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system.

[0007] Beneficial effects of the present invention: The method for determining the DOP value of the orbital clock error of a low-orbit satellite provided by the present invention obtains the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in an earth-fixed coordinate system according to the measurement geometry of the low-orbit satellite facing the GNSS satellite and the carrier phase and pseudorange ionosphere-free combined observation equation corresponding to the current orbit determination method; determines the precision factor DOP value of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system according to the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system, and can calculate the precision factor DOP value of the precise orbit determination and timing of the low-orbit satellite based on the carrier phase and pseudorange observations. Based on this method, when the true result of the precise orbit determination and timing of the low-orbit satellite cannot be obtained, the DOP values ​​of the precision factors are obtained by calculation, and then the strength of the observation model can be described according to the DOP values ​​of the precision factors, the formal precision of each parameter is calculated, and the correlation between the parameters is solved.

[0008] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic flow chart of a method for determining a DOP value of a low-orbit satellite provided by the present invention; Figure 2 A schematic diagram of the structure of a device for determining the DOP value of a low-orbit satellite provided by the present invention. DETAILED DESCRIPTION

[0010] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0011] The present invention aims to provide a method for calculating the DOP value of the precision factor of orbit radial, tangential and normal parameters and the clock error parameters of low-orbit satellites based on a simplified dynamics / kinematics low-orbit satellite precise orbit determination and timing method based on dual-frequency carrier phase and pseudorange for single GNSS system / multi-GNSS system, so as to facilitate the description of the strength of the observation model and the formal precision of the calculation parameters and obtain the correlation between the parameters.

[0012] Figure 1A flow chart of a method for determining a DOP value of a low-orbit satellite provided by the present invention is shown in FIG. Figure 1 As shown, the method includes: S101. According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained.

[0013] The orbit determination method can be the simplified dynamic orbit determination method of low-orbit satellites or the kinematic orbit determination method of low-orbit satellites. Specifically, when the dynamic orbit determination capability is not available or the orbit is maneuvered, resulting in the lack of maneuverable orbit determination capability, the kinematic orbit determination method of low-orbit satellites can be used.

[0014] In a possible implementation, when the current orbit determination method is a simplified dynamic orbit determination method for low-orbit satellites, according to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained, including the following steps a1-a3: a1. According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the simplified dynamical orbit determination method of the low-orbit satellite, the formal covariance matrix of all solution parameters corresponding to the simplified dynamical orbit determination method of the low-orbit satellite is obtained, which is expressed as: , in, The formal covariance matrix representing all solution parameters corresponding to the simplified dynamics orbit determination method for low-orbit satellites, represents the first design matrix, which contains the partial derivatives of all observation data for all solution parameters corresponding to the simplified dynamics orbit determination method for low-orbit satellites, represents the covariance matrix of the observed data, with the superscript Indicates transpose.

[0015] a2. According to the formal covariance matrix of all parameters corresponding to the simplified dynamics orbit determination method of low-orbit satellite, the dynamics parameters and The formal covariance matrix of the epoch clock error parameters is expressed as: , in, Indicates that the dynamic parameters of the low-orbit satellite and Epoch clock error parameters, represents the dynamic parameters of low-orbit satellites and The epoch clock error parameters are in the form of a covariance matrix.

[0016] a3. According to The partial derivative matrix of the LEO satellite orbit to the LEO satellite dynamic parameters in the epoch inertial coordinate system, the rotation matrix from the inertial coordinate system to the earth-fixed coordinate system, and the LEO satellite dynamic parameters and The form covariance matrix of the epoch clock error parameters is obtained The formal covariance matrix of the orbit and clock parameters of the low-orbit satellite in the epoch earth-fixed coordinate system is expressed as: , , in, express The formal covariance matrix of the orbit and clock parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system is: express epoch parameter conversion matrix, express The rotation matrix from the epoch inertial coordinate system to the Earth-fixed coordinate system, express Partial derivative matrix of LEO satellite orbit with respect to LEO satellite dynamic parameters in epoch-inertial coordinate system.

[0017] In a possible implementation, when the current orbit determination method is a low-orbit satellite kinematic orbit determination method, according to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained, including the following steps b1-b2: b1. According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the low-orbit satellite kinematic orbit determination method, the formal covariance matrix of all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method is obtained, which is expressed as: , in, The formal covariance matrix representing all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method, represents the second design matrix, which contains the partial derivatives of all observation data with respect to all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method. Represents the covariance matrix of the observed data.

[0018] b2. According to the formal covariance matrix of all parameters corresponding to the low-orbit satellite kinematic orbit determination method, we can obtain The formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch earth-fixed coordinate system is expressed as: , in, express The formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, Select from all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method Kinematic orbit and clock error parameters of low-orbit satellites in the epoch Earth-fixed coordinate system.

[0019] S102: Determine the DOP value of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system according to the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system.

[0020] The DOP is a core indicator for evaluating the quality of satellite navigation positioning, and is used to quantify the amplification effect of satellite geometric distribution on positioning errors. The smaller the DOP value, the more conducive the satellite spatial distribution is to high-precision positioning.

[0021] In a possible implementation, when the current orbit determination method is a simplified dynamic orbit determination method for low-orbit satellites, the precision factor DOP value of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system is determined according to the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system, which is expressed as: , , , , Among them, the general formula represent The covariance matrix of the dynamic orbit and clock parameters of low-orbit satellites in the epoch Earth-fixed coordinate system is Line The elements of the column, , , (1,1) in the above formula means The elements of the first row and first column of the covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (2,2) represent The element of the 2nd row and 2nd column of the covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (3,3) represents The element of the third row and third column of the formal covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (4,4) represents The elements of the 4th row and 4th column of the formal covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system are: represents the root mean square (RMS) of observations with unit weight, express The DOP value of the epoch low-orbit satellite dynamic orbit in the X-axis direction of the earth-fixed coordinate system, express The DOP value of the epoch low-orbit satellite dynamic orbit in the Y-axis direction of the earth-fixed coordinate system, express The DOP value of the epoch low-orbit satellite dynamic orbit in the Z-axis direction of the earth-fixed coordinate system, express The DOP value of the precision of the clock error parameters in the simplified dynamic orbit determination mode of the epoch low-orbit satellite.

[0022] Specifically, It can be either a priori RMS or a posteriori RMS, the a priori or posteriori depends on the covariance matrix of the observed data Whether prior or posterior data were used.

[0023] In another possible implementation, when the current orbit determination method is a simplified dynamic orbit determination method for low-orbit satellites, the precision factor DOP value of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system is determined according to the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system, which is expressed as: , , , in, , , , , , , express The covariance matrix of radial, tangential, normal orbit and clock error parameters of low-orbit satellite dynamics in the epoch Earth-fixed coordinate system, express The rotation matrix from the epoch Earth-fixed coordinate system to the orbital coordinate system, express The DOP value of the dynamic radial orbit of the epoch low-orbit satellite, express The DOP value of the dynamic tangential orbit of the epoch low-orbit satellite, express The DOP value of the dynamic normal orbit of the epoch low-orbit satellite, express The DOP value of the precision of the clock error parameters in the simplified dynamic orbit determination mode of the epoch low-orbit satellite. The correlation factor between the radial orbit and clock error parameters of the LEO satellite dynamics, Represents the correlation factor between the dynamic tangential orbit and clock error parameters of the low-orbit satellite, Represents the correlation factor between the LEO satellite dynamics normal orbit and clock error parameters, express epoch LEO satellite positions, express The velocity of the low-orbit satellite in the epoch is given by represent The covariance matrix of the dynamic orbit and clock parameters of low-orbit satellites in the epoch Earth-fixed coordinate system is Line The elements of the column, , , in the above formula (1,1) means The elements of the first row and first column of the covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (2,2) represent The element of the 2nd row and 2nd column of the covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (3,3) represents The element of the third row and third column of the formal covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (4,4) represents The element of the 4th row and 4th column of the formal covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (1,4) represents The element of the first row and fourth column of the formal covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (2,4) represents The element of the 2nd row and 4th column of the formal covariance matrix of the dynamic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (3,4) represents The elements in the third row and fourth column of the formal covariance matrix of the dynamical orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system.

[0024] In a possible implementation, when the current orbit determination method is a low-orbit satellite kinematic orbit determination method, the precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is determined according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system, which is expressed as: , , , , Among them, the general formula represent The form of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system is Line The elements of the column, , , (1,1) means The elements of the first row and first column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (2,2) represent The elements of the 2nd row and 2nd column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (3,3) represent The elements of the third row and third column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (4,4) represent The elements of the 4th row and 4th column of the formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system are: express The DOP value of the precision factor of the epoch low-orbit satellite kinematic orbit in the X-axis direction of the earth-fixed coordinate system, express The DOP value of the precision factor of the epoch low-orbit satellite kinematic orbit in the Y-axis direction of the earth-fixed coordinate system, express The DOP value of the precision factor of the epoch low-orbit satellite kinematic orbit in the Z-axis direction of the earth-fixed coordinate system, express The DOP value of the clock error parameters in the epoch low-orbit satellite kinematic orbit determination mode, express The covariance matrix of the epoch low-orbit satellite kinematic orbit and clock parameters, represents the root mean square of the observations with unit weight.

[0025] In another possible implementation, when the current orbit determination method is a low-orbit satellite kinematic orbit determination method, the precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is determined according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system, which is expressed as: , , , in, , , , , , express The covariance matrix of the radial, tangential, normal orbit and clock error parameters of the low-orbit satellite kinematics in the epoch earth-fixed coordinate system, express The rotation matrix of the LEO satellite kinematic orbit to the LEO satellite kinematic radial, tangential and normal orbits in the epoch earth-fixed system, Represents the correlation factor between the radial orbit and clock error parameters of the low-orbit satellite kinematics, Represents the correlation factor between the kinematic tangential orbit and clock error parameters of the low-orbit satellite, Represents the correlation factor between the kinematic normal orbit and clock error parameters of the low-orbit satellite, express The DOP value of the kinematic radial orbit of the epoch low-orbit satellite, express The DOP value of the tangential orbit of the epoch low-orbit satellite kinematics, express The DOP value of the kinematic normal orbit of the epoch low-orbit satellite, express The precision factor DOP value of the clock error parameter in the epoch low-orbit satellite kinematic orbit determination mode is as follows: represent The form of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system is Line The elements of the column, , , (1,1) means The elements of the first row and first column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (2,2) represent The elements of the 2nd row and 2nd column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (3,3) represent The elements of the third row and third column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (4,4) represent The element of the 4th row and 4th column of the formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (1,4) represents The elements of the first row and fourth column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (2,4) represent The elements of the 2nd row and 4th column of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, (3,4) represent The elements in the 3rd row and 4th column of the formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system.

[0026] This method proposes different precision factor DOP value calculation methods for the simplified dynamic orbit determination method and the kinematic orbit determination method for low-orbit satellites, and gives the precision factor DOP value calculation process of different methods from different dimensions, which can improve the calculation accuracy.

[0027] The present invention provides a method and device for determining the DOP value of a low-orbit satellite. The method and device obtain the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in a ground-fixed coordinate system based on the measurement geometry of the low-orbit satellite facing the GNSS satellite and the carrier phase and pseudorange ionosphere-free combined observation equation corresponding to the current orbit determination method; determine the precision factor DOP value of the orbit and clock error parameters of the low-orbit satellite in the ground-fixed coordinate system based on the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the ground-fixed coordinate system, and can calculate the precision factor DOP value of the precise orbit determination and timing of the low-orbit satellite based on the carrier phase and pseudorange observations. Based on this method, when the true accuracy of the precise orbit determination and timing of the low-orbit satellite cannot be obtained, the precision factor DOP values ​​are obtained by calculation, and then the strength of the observation model can be described according to the precision factor DOP values, the formal accuracy of each parameter is calculated, and the correlation between the parameters is solved.

[0028] Figure 2 A schematic diagram of the structure of a device for determining the DOP value of a low-orbit satellite provided by the present invention is shown in FIG. Figure 2 As shown, the device comprises: The first processing module 21 is used to obtain the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system according to the measurement geometry of the low-orbit satellite facing the GNSS satellite and based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method; The second processing module 22 is used to determine the precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system.

[0029] The present invention also provides a structure of an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus. Memory, used to store computer programs; The processor is used to implement the steps provided in the above method embodiment when executing the program stored in the memory.

[0030] The communication interface is used for communication between the above electronic device and other devices.

[0031] The method provided in the embodiment of the present invention can be applied to electronic devices. Specifically, the electronic device can be: a desktop computer, a portable computer, an intelligent mobile terminal, a server, etc. This is not limited here, and any electronic device that can implement the present invention belongs to the protection scope of the present invention.

[0032] The present invention also provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps provided in the above method embodiment are implemented.

[0033] As for the device / electronic device / storage medium embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the specific content and beneficial effects and other related matters can be referred to the partial description of the method embodiment.

[0034] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for determining the orbital clock error DOP value of a low-orbit satellite, characterized in that: include: According to the measurement geometry of the low-orbit satellite facing the global satellite positioning system GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained; According to the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system, the precision factor DOP value of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system is determined.

2. The method according to claim 1, characterized in that When the current orbit determination method is a simplified dynamic orbit determination method for low-orbit satellites, According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained, including: According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the simplified dynamical orbit determination method of the low-orbit satellite, the formal covariance matrix of all solution parameters corresponding to the simplified dynamical orbit determination method of the low-orbit satellite is obtained, which is expressed as: ， in, The formal covariance matrix representing all solution parameters corresponding to the simplified dynamics orbit determination method for low-orbit satellites, represents the first design matrix, which contains the partial derivatives of all observation data for all solution parameters corresponding to the simplified dynamics orbit determination method for low-orbit satellites, represents the covariance matrix of the observed data, with the superscript represents transpose; According to the formal covariance matrix of all parameters corresponding to the simplified dynamics orbit determination method of low-orbit satellite, the dynamics parameters and The formal covariance matrix of the epoch clock error parameters is expressed as: ， in, Indicates that the dynamic parameters of the low-orbit satellite to be solved are selected from all the solution parameters corresponding to the simplified dynamic orbit determination method of the low-orbit satellite and Epoch clock error parameters, represents the dynamic parameters of low-orbit satellites and The formal covariance matrix of the epoch clock error parameters; according to The partial derivative matrix of the low-orbit satellite orbit to the low-orbit satellite dynamic parameters in the epoch inertial coordinate system, the rotation matrix from the inertial coordinate system to the earth-fixed coordinate system, and the low-orbit satellite dynamic parameters and The form covariance matrix of the epoch clock error parameters is obtained The formal covariance matrix of the dynamic orbit and clock parameters of the low-orbit satellite in the epoch earth-fixed coordinate system is expressed as: ， ， in, express The formal covariance matrix of the dynamic orbit and clock parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system is: express epoch parameter conversion matrix, express The rotation matrix from the epoch inertial coordinate system to the Earth-fixed coordinate system, express The partial derivative matrix of the dynamical orbit of the low-orbit satellite with respect to the dynamical parameters of the low-orbit satellite in the epoch-inertial coordinate system.

3. The method according to claim 1, characterized in that When the current orbit determination method is a low-orbit satellite kinematic orbit determination method, According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method, the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is obtained, including: According to the measurement geometry of the low-orbit satellite facing the GNSS satellite, based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the low-orbit satellite kinematic orbit determination method, the formal covariance matrix of all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method is obtained, which is expressed as: ， in, The formal covariance matrix representing all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method, represents the second design matrix, which contains the partial derivatives of all observation data with respect to all solution parameters corresponding to the low-orbit satellite kinematic orbit determination method. Represents the covariance matrix of the observed data; According to the formal covariance matrix of all parameters corresponding to the LEO satellite kinematic orbit determination method, we can obtain The formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch earth-fixed coordinate system is expressed as: ， in, express The formal covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system, Select the solution from all the solution parameters corresponding to the low-orbit satellite kinematic orbit determination method Kinematic orbit and clock error parameters of low-orbit satellites in the epoch Earth-fixed coordinate system.

4. The method according to claim 2, characterized in that: The precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is determined according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system, which is expressed as: ， ， ， ， Among them, the general formula represent The covariance matrix of the dynamic orbit and clock parameters of low-orbit satellites in the epoch Earth-fixed coordinate system is Line The elements of the column, , , represents the root mean square RMS of the observations with unit weight, express The DOP value of the epoch low-orbit satellite dynamic orbit in the X-axis direction of the earth-fixed coordinate system, express The DOP value of the epoch low-orbit satellite dynamic orbit in the Y-axis direction of the earth-fixed coordinate system, express The DOP value of the epoch low-orbit satellite dynamic orbit in the Z-axis direction of the earth-fixed coordinate system, express The DOP value of the precision of the clock error parameters in the simplified dynamic orbit determination mode of the epoch low-orbit satellite.

5. The method according to claim 2, characterized in that: The precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is determined according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system, which is expressed as: ， ， ， in, ， ， ， ， ， ， express The covariance matrix of radial, tangential, normal orbit and clock error parameters of low-orbit satellite dynamics in the epoch Earth-fixed coordinate system, express The rotation matrix from the epoch Earth-fixed coordinate system to the orbital coordinate system, express The DOP value of the dynamic radial orbit of the epoch low-orbit satellite, express The DOP value of the dynamic tangential orbit of the epoch low-orbit satellite, express The DOP value of the dynamic normal orbit of the epoch low-orbit satellite, express The DOP value of the precision of the clock error parameters in the simplified dynamic orbit determination mode of the epoch low-orbit satellite, The correlation factor between the radial orbit and clock error parameters of the LEO satellite dynamics, Represents the correlation factor between the dynamic tangential orbit and clock error parameters of the low-orbit satellite, Represents the correlation factor between the LEO satellite dynamics normal orbit and clock error parameters, express epoch LEO satellite positions, express The velocity of the low-orbit satellite in the epoch is given by represent The covariance matrix of the dynamic orbit and clock parameters of low-orbit satellites in the epoch Earth-fixed coordinate system is Line The elements of the column, , .

6. The method according to claim 3, characterized in that The precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is determined according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system, which is expressed as ， ， ， ， Among them, the general formula represent The form of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system is Line The elements of the column, , , express The DOP value of the precision factor of the epoch low-orbit satellite kinematic orbit in the X-axis direction of the earth-fixed coordinate system, express The DOP value of the precision factor of the epoch low-orbit satellite kinematic orbit in the Y-axis direction of the earth-fixed coordinate system, express The DOP value of the precision factor of the epoch low-orbit satellite kinematic orbit in the Z-axis direction of the earth-fixed coordinate system, express The DOP value of the precision of the clock error parameters in the epoch kinematic orbit determination mode, express The covariance matrix of the epoch low-orbit satellite kinematic orbit and clock parameters, represents the root mean square of the observations with unit weight.

7. The method according to claim 3, characterized in that The precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system is determined according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system, which is expressed as: ， ， ， in, ， ， ， ， express The covariance matrix of the radial, tangential, normal orbit and clock error parameters of the low-orbit satellite kinematics in the epoch earth-fixed coordinate system, express The rotation matrix of the LEO satellite kinematic orbit to the LEO satellite kinematic radial, tangential and normal orbits in the epoch earth-fixed system, Represents the correlation factor between the radial orbit and clock error parameters of the low-orbit satellite kinematics, Represents the correlation factor between the kinematic tangential orbit and clock error parameters of the low-orbit satellite, Represents the correlation factor between the kinematic normal orbit and clock error parameters of the low-orbit satellite, express The DOP value of the kinematic radial orbit of the epoch low-orbit satellite, express The DOP value of the tangential orbit of the epoch low-orbit satellite kinematics, express The DOP value of the kinematic normal orbit of the epoch low-orbit satellite, express The precision factor DOP value of the clock error parameter in the epoch kinematic orbit determination mode is as follows: represent The form of the covariance matrix of the kinematic orbit and clock error parameters of the low-orbit satellite in the epoch Earth-fixed coordinate system is Line The elements of the column, , .

8. A device for determining the DOP value of a low-orbit satellite, characterized in that: include: The first processing module is used to obtain the formal covariance matrix of the orbit and clock error parameters of the low-orbit satellite in the earth-fixed coordinate system according to the measurement geometry of the low-orbit satellite facing the GNSS satellite and based on the carrier phase and pseudo-range ionosphere-free combined observation equation corresponding to the current orbit determination method; The second processing module is used to determine the precision factor DOP value of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system according to the formal covariance matrix of the low-orbit satellite orbit and clock error parameters in the earth-fixed coordinate system.

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